Omega Fornacis, which is Latinized from ω Fornacis, is a wide binary star[11] system in the southern constellation of Fornax. It has a blue-white hue and is faintly visible to the naked eye as a fifth-magnitude star.[6] The system lies at a distance of approximately 470 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +10 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Fornax |
| Right ascension | 2h 33m 50.70081s[1] |
| Declination | –28° 13′ 56.3890″[1] |
| Apparent magnitude (V) | 4.95 + 7.71[2] |
| Characteristics | |
| A | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B9V[4] |
| U−B color index | −0.13[5] |
| B−V color index | −0.050±0.007[6] |
| R−I color index | −0.07[5] |
| B | |
| Spectral type | A3V[7] |
| U−B color index | +0.09[8] |
| B−V color index | +0.17[8] |
| Astrometry | |
| Radial velocity (Rv) | +9.7±2.8[6] km/s |
| Proper motion (μ) | RA: −13.290±0.243[1] mas/yr Dec.: −5.532±0.305[1] mas/yr |
| Parallax (π) | 7.0025 ± 0.1527 mas[1] |
| Distance | 470 ± 10 ly (143 ± 3 pc) |
| Absolute magnitude (MV) | -0.87[6] |
| Details | |
| A | |
| Mass | 3.42±0.11[3] M☉ |
| Radius | 2.81[7] R☉ |
| Luminosity | 268+72 −57[3] L☉ |
| Temperature | 10,910±420[9] K |
| Rotational velocity (v sin i) | 85±13[7] km/s |
| B | |
| Radius | 2.2[7] R☉ |
| Rotational velocity (v sin i) | 180±29[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The dual nature of this system was discovered in 1836 by John Herschel. As of 2013, the two components had an angular separation of 11.0″ along a position angle of 246°.[2] This corresponds to a projected separation of 1,520 AU.[7]
The magnitude 4.95[2] primary, designated component A, is a chemically peculiar[3] B-type main-sequence star with a stellar classification of B9V[4] It has 3.4[3] times the Sun's mass and is radiating around 268[3] times the luminosity of the Sun from its photosphere at an effective temperature of 10,910 K.[9] Component B, the magnitude 7.71[2] secondary, is an A-type main-sequence star with a class of A3V.[7] It is smaller than the primary, but has a higher projected rotational velocity.[7]
References
edit- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
- ^ a b c d e f Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ a b Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
- ^ a b Hoffleit, D.; Warren, Jr., W. H. (1991). "VizieR Detailed Page". Bright Star Catalogue (5th Revised ed.). CDS. Retrieved 2012-07-13.
- ^ a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
- ^ a b c d e f g h Howe, K. S.; Clarke, C. J. (January 2009). "An analysis of v sin (i) correlations in early-type binaries". Monthly Notices of the Royal Astronomical Society. 392 (1): 448–454. Bibcode:2009MNRAS.392..448H. doi:10.1111/j.1365-2966.2008.14073.x.
- ^ a b Corbally, C. J. (1984). "Close visual binaries. I - MK classifications". Astrophysical Journal Supplement Series. 55: 657. Bibcode:1984ApJS...55..657C. doi:10.1086/190973.
- ^ a b Zorec, J.; et al. (2009). "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff". Astronomy and Astrophysics. 501 (1): 297–320. arXiv:0903.5134. Bibcode:2009A&A...501..297Z. doi:10.1051/0004-6361/200811147. S2CID 14969137.
- ^ "ome For". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-29.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.Vizier catalog entry